1. The Oxygen Cycle Kevin Kwong and John Solder 9.6 x10^9 kg 1.4 x10^18 kg 2.9 x10^20 kg 1.6 x10^16 kg Modified from http://ilc.royalsaskmuseum.ca/ilc6/pages/62b/63e/pf63ep2p1.htm

2. Fluxes and Residence Reservoir Capacity (kg O 2 ) (10 20 ) Flux In/Out (kg O 2 /year)(10 10 ) Residence Time (years) Atmosphere 0.01430,0004,500 Biosphere 0.0001630,00050 Lithosphere 2.9605*10 8 Hydrosphere.0000000009645021 *10 6

3. Hydrosphere Calculation Sea-Surface Dissolved Oxygen (0~600 m) 5.4 x 10^16 mol Anoxic Zone (600~1100 m) Very Low DO Deep Ocean (1100~4000 m) 2.08 x 10^20 mol X 32 g/mol => 6.65 x10^18 kg O2

4. Photosynthesis and Respiration   6CO 2 + 6H 2 O + Energy → C 6 H 12 O 6 + 6O 2   C 6 H 12 O 6 + 6O 2 →6 CO 2 + 6H 2 O + Energy   686 Kcal is the amount of energy imputed and released from these systems

5. Photodissociation  Breakdown of Ozone by Photons. O 3 + hν → O 2 + O @ λ ~240-310 nm O 3 + O → 2 O 2 2 O → O 2   The overall amount of ozone in the stratosphere is determined by a balance between production by solar radiation, and removal. The removal rate is slow, since the concentration of O atoms is very low. Weathering and Deposition  Oxidation of Earth Materials. 4FeO + O 2 → 2Fe 2 O 3 2 Ni + O 2 = 2 NiO 2 Fe + SiO 2 + O 2 = Fe 2 SiO 4  Biological Weathering releases O2 from minerals as other nutrients are consumed. (Chelate compounds)   Corals and shells of marine organisms are O rich (CaCO3), becomes limestone.